Looks interesting. If it's as scalable and performant as they claim (and it seems to be doing just fine on Walmart's heavy usage), then this could be great for future large projects. And I would hope that Walmart's backing of this project will keep it supported without breaking changes for long enough that it would be viable for use in very large production apps.
The negative I see here is that we now have yet another JS/React app platform. As someone who is just diving into using JS framework/library-backed applications in web development, it just makes figuring out what everything is the JS ecosystem actually does to support a large application that much more confusing.
Choice isn't a bad thing per-say, but too much choice can make getting up to speed more difficult. Given, however, this platform appears to be intended for large applications that require scalability, rather than for small apps being built for learning.